Welcome to this fun and easy project where we create a USB-powered wireless LED setup using recycled parts and simple components. By winding a center-tapped coil and using inductive coupling, you can wirelessly power multiple 5mm LEDs in different colors, creating a cool glowing effect without the need for any direct connections.
This project is a great way to recycle old LED bulbs and gives you a hands-on understanding of wireless energy transfer. Plus, it’s compact, portable, and can run off a USB charger or power bank!
For the base of this project, I used 8mm thick acrylic. I started by cutting a round disc with a diameter of 2.4 cm using a hole saw (or laser cutter, depending on your tools).
Apply a small drop of super glue (or hot glue) onto the center of the acrylic base.
Carefully place the USB male connector on the glued spot and hold it in place for a few seconds until it sets firmly.
⚠️ Make sure the USB connector is aligned properly and stands straight for a clean and professional look.
Insert the D882 transistor near the USB connector.
Trim its legs as shown in the reference photo to make it more compact.
Then, solder the 3rd leg (Emitter) of the transistor to the negative (GND) pin of the USB male connector.
Once positioned correctly, apply a small amount of super glue or hot glue to the base of the transistor to secure it firmly to the acrylic base.
🔧 Double-check the pinout of the D882:
1st leg – Base
2nd leg – Collector
3rd leg – Emitter
Take the 3-pin terminal block and apply a small amount of glue to its base.
Carefully place and stick it onto the side of the acrylic base, making sure it’s aligned neatly and firmly attached.
💡 Position it so the wire connections will be easy to reach and solder in the next steps.
Use a piece of thick copper wire to make the connection between the 1st pin of the 3-pin terminal block and the 3rd leg (Emitter) of the D882 transistor.
Before soldering the copper wire, insert a 1kΩ resistor between the copper wire and the transistor’s 3rd leg.
This resistor will help regulate the current and protect the circuit.
Once everything is aligned, solder the resistor and wire securely in place.
🔥 Make sure there are no loose joints—this part carries current to the LED.
First, solder the +V pin of the USB male connector (usually the outermost pin) directly to the center pin of the 3-pin terminal block.
This will supply power to your connected LED or load.
Next, use a thick copper wire to connect the center pin of the 3-pin terminal block to the 3rd leg (Collector) of the D882 transistor.
⚡ Ensure that the copper wire is securely soldered for reliable current flow.
Make a small hole in the acrylic base near the D882 transistor for the heatsink.
Apply a small amount of thermal paste to the top of the transistor to improve heat transfer between the transistor and the heatsink.
Next, position the heatsink onto the transistor and screw it in place through the hole in the acrylic to ensure it is securely attached.
❄️ The thermal paste helps dissipate heat more effectively, keeping the transistor cool when driving the LED.
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Drill a small hole in the center of the acrylic base.
Then, insert an M2 spacer into the hole. This spacer will act as a support or mounting point for the upper part of your setup
Using 32 SWG insulated copper wire, wind a coil with a total of 30 turns, center-tapped:
- Wind 15 turns, then create a small loop or tap (this will be your center tap).
- Continue winding 15 more turns in the same direction to complete the 15-0-15 coil.
After winding:
- Scratch the insulation from the ends of all three coil wires (two ends + center tap) to prepare them for soldering.
- Use insulation tape to tightly wrap and secure the coil so it stays firmly in shape.
🌀 Neat winding and proper insulation removal are important for stable connections and performance.
Take the three ends of the coil (start, center tap, and end) and insert them into the 3-pin terminal block:
- One wire in each pin:
- Start of the coil → 1st pin
- Center tap → Center pin
- End of the coil → 3rd pin
Once inserted, tighten the screws on the terminal block to securely hold the wires in place.
Cut another 2.4 cm diameter round disc from clear acrylic (same as the base).
Drill a small hole in the center of this acrylic disc.
Place it over the M2 spacer installed earlier, and secure it with a screw to complete the top cover.
To make Inductor LEDs, you can reuse parts from old LED bulb drivers:
- Open up an old or faulty LED bulb and carefully remove the internal driver board.
- On the driver board, locate and desolder the inductor (a small coil or ring with copper wire).
- Take a 5mm LED (any color you like) and solder it directly onto the legs of the inductor.
⚠️ There is no polarity for this setup—either LED leg can go to either inductor terminal.
This setup works by picking up a weak magnetic field from the coil you made earlier and lighting up the LEDs wirelessly.
🌈 Use different colored LEDs for a cool multi-color effect!
With everything assembled, plug the USB connector into a USB charger or power bank.
Now, take your inductor LEDs and place them on top of the potentiometer, right over the clear top acrylic disc.
✨ And just like magic—they glow wirelessly!
🔥 It works using inductive coupling—your center-tapped coil creates a small oscillating field that powers the LEDs without any direct contact!
This project is portable — just plug it into any USB power bank, and it works exactly the same way!
You can carry it around and place your inductor LEDs anywhere on the top disc to see them glow wirelessly, even without being plugged into a wall.
🧲 Perfect for showing off wireless energy transfer at school, maker fairs, or just as a cool desk toy!
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